HYDRO21155

• Permit No: M1992069
• IBM Index Class Name: Hydrology
• Doc Date: 11/19/2001
• Doc Name: OCTOBER 2001 QUARTERLY MONITORING REPORT AGGREGATE INDUSTRIES F ST FACILITY
• From: PARAGON
• To: DMG
• Media Type: D
• Archive: No

Ms. Connie Davis/Aggregate Industries - F Stree[ October 2001 QMR
Project Number [001018 PnRncoN
November 16, 2001
Page 5
Basic Standards for Ground Water" Regulation 4l, (5 CCR 1002-41). It should be noted
that TEPH is not regulated by a numeric standard in Colorado at this time. As seen from
Table 2, BTEX concentrations observed in the groundwater samples collected from the site
during October 2001 did not exceed the CGS.
5. SURFACE WATER QUALITY RESULTS
A surface water sample was collected from the North Dewatering Trench on October l8,
2001 at the request of Ms. Kate Pickford of the DMG. The surface water sample was
transported under standard Paragon chain-of-custody procedures to TLI for BTEX and TEPH
analyses using EPA Methods 82b0 and Modified 8015, respectively. Laboratory results for
surface water samples collected from the site between May 2001 and October 2001 are
summarized in Table 3. Copies of the TLI laboratory reports are also attached to this report.
As seen in Table 3, BTEX and TEPH concentrations were not observed above the laboratory
detection limits of 0.5 µg/L and 0.5 mg/L, respectively in the surface water sample collected
from the North Dewatering Trench on October 18, 2001.
The Surface Water Standards for benzene, toluene and ethylbenzene are also summarized in
Table 3. As seen from Table 3, the standards for benzene, toluene and ethylbenzene are 71;
17,500; and 29,000 µg/L, respectively. The standards for benzene and ethylbenzene are the
fists ingestion standards while the standard for toluene is the acute, aquatic-life based
standard published in "The Basic Standards and Methodologies for Surface Water"
Regulation 31 (5 CCR 1002-31). Xylenes and TEPH are not currently regulated by a
numeric standard. The benzene, toluene and ethylbenzene concentrations observed in the
surface water sample collected from the North Dewatering Trench on October l8, 2001 did
not exceed the Surface Water Standards.
6. CONCLUSIONS AND RECOMMENDATIONS
The following conclusions are made based on information obtained during the quarterly
groundwater sampling activities and additional assessment activities.
1. Groundwater was observed at depths ranging from approximately 5.9 to 24.2 feet below
grade during the October 2001 sampling event. Free-phase product was not observed
during the October 2001 sampling episode.
2. The regional groundwater flow generally appears to be in a northeasterly direction with a
more northerly component on the east side of the site while the local groundwater flow
direction appears to be to the northeast in the vicinity of the spill area with a more